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I created a "TCApp.BTM" that just echos something and waits for a key before quitting. I tried starting AppDispatch.BTM with an "auto" argument and ran the batch debugger both from a TCC console window and a TCMD tab window. It worked perfectly chaining directly in both cases (and also when using CALL).
You say that chaining is "crashing the debugger" - are you actually getting a crash dialog from Windows? If so, please send the contents of that dialog. (And if you are, it's almost certainly coming either from Windows or from third-party injected code, as IDE does its own exception handling.)
If IDE is crashing in its internal code, it will create a log file named "IDE.exception.log". If you have that file, please post it here. (If you don't have it, the crash isn't in IDE.EXE.)
IDE will load yout TCMD.INI and your plugins and run TCSTART before launching the batch file, so try starting IDE with the /I option to disable TCMD.INI, plugins, and TCSTART.